Power wrench for oil field uses



2 Sheets-Sheet 2 c. H. WILMETH POWER WRENCH FOR OIL FIELD USES March 3, 1970 Filed Sept. 26, 19s? Z 38 EN TOR. C2 flt/OfflMl mar/r United States Patent O US. Cl. 81-57 7 Claims ABSTRACT OF THE DISCLOSURE An improved power driven wrench is described, and the wrench has special features of construction which meet specific needs of oil field uses wherein a power wrench must be used in confined places for tightening or loosening nuts and other connectors. The improved wrench includes an uninterrupted socket member having integral gear teeth formed about its periphery for being driven by a detachable power means. The gear driven socket member is mounted between bearing plates included within a very thin housing, and the housing includes means for preventing the wrench from whipping or swinging about when power is applied to it. Also, the housing is constructed to provide for an inspection of gear teeth carried by the socket member.

BRIEF DESCRIPTION AND BACKGROUND OF INVENTION This invention relates to improvements in power driven socket wrenches, and the improvements include features which make a wrench more adaptable for use in oil field requirements of handling nuts and other connectors associated with oil well casing columns and installations.

It is known in the prior art to provide for closed and open-ended trench devices which may be manually operated or driven from a source of power. For example, Fish Patent 2,787,180 and Ulrich et al. Patent 3,257,877 each disclose wrench devices having open-ended sockets which can be slid around a nut or bolt head to apply a torque thereto. Closed socket wrench structures are illustrated in the patents to Strand 1,384,811, Wehner 2,481,633, De Note 2,629,278, De Note 2,664,020, and Shatf 2,693,728. Generally, prior art structures have provided for some means of supporting a socket member within a wrench structure, and means are included for driving the socket member either manually or by the application of power from a source. However, despite the numerous structures which have been developed, and which have been marketed, no prior wrench device has been suitable for safe .use in the oil field where it is necessary to work within confined places and in areas which are otherwise dangerous when power tools are normally utilized. The present invention is concerned with the special needs of the oil industry, and in view of these needs, a novel wrench structure has been created for safe use by workers in oil fields.

For some time, it has been a practice in the oil industry to attach flanged valves to oil well drilling casing columns for blow-out prevention, and the installation and securing of flanged valves and other similar units has been a laborious and dangerous operation. In the usual operation of connecting a flanged valve to a well casing, a first flange is welded or threaded to the top of the casing, and subsequent flanged units are secured to the casing flange and to each other with suitable seals or gaskets between the flanges. The securing of adjacent flanges together is accomplished by the use of threaded stud bolts and nuts, or other connectors which require the turning of a nut over a threaded rod. The flanges include openings through which the stud bolts can be inserted, and nuts are then installed onto the threaded ends of the stud bolts and turned until the faces of the nuts engage the face of a flange. Although this operation may be ideally accomplished by the use of hands if threads are perfect and clean, it has been more typical to utilize a wrench to tighten or loosen nuts from stud bolts and such connections. The environment in which such work is performed is'generally unsafe because the flanges which are to be connected are positioned in confined places, often below the surface of the earth, and quantities of oil, grease, mud, and other foreign matter are likely to exist in and around the well pit. Due to the configuration of the various units that are typically used to make up a blowout preventing system, and because of the confined working conditions found around a well, there has been no attempt to use power wrenches in this confined and somewhat dangerous environment of oil fields. Thus, it has been a practice to utilize a hand wrench together with a sledge hammer for final tightening of nuts on connectors.

A standard practice in the oil well industry has been for two workers to cooperate in a single confined area to tighten nuts on connectors for well equipment. One worker is required to hold a hand wrench in place, and because of the confined area in which the work is performed, a second worker has been required to swing a sledge hammer to strike the handle of the wrench. There is usually no good footing area for the workmen to stand upon, and thus, a slight miscalculation by one of the two workers can result in a serious accident. In fact, accidents of this type are a known and expected thing in the oil industry because of limitations of prior tools which have been used by the workmen.

The present invention provides, for the first time, a power wrench which can be applied and used by a single person to install blow-out preventors, and other equipment, on well casings. The wrench of this invention is constructed in a special manner to overcome the confined working conditions encountered in oil fields, and the construction includes features which make the wrench safer for use than any known prior wrench device.

The improved power wrench of this invention includes a two-piece housing which is rugged and easily assembled. Included within the housing is a socket member enclosed within a complete circle of gear teeth, and a worm gear is provided for directly driving the socket member and for multiplying torque on the socket without the use of intermediate gears. The housing is constructed to completely protect the gears of the socket member, and yet, provision is made for visually inspecting the condition of the socket gear without requiring a substantial protrusion of gear teeth outside of the confines of the housing.

The two-piece housing is very thin in its construction, and the driving mechanism is completely enclosed within the housing without a requirement for protruding or exposed parts. The housing is also constructed to include protruding bearing surfaces which extend on its outside corners for limiting movement of the power wrench relative to a casing or any nearby structure next to which the tool is being used. The protruding or extended portions of the housing are constructed to prevent any whipping or swinging of the entire tool when the wrench is placed over a nut and power is applied to turn the nut. This feature is especially important to the present invention because it is not safe for workmen in an oil field environment to resist swinging and whipping of a power wrench by their own manual efforts. The protruding bearing surfaces, which hereafter will be referred to as extended portions, are preferably positioned at opposite corners along one edge of the wrench so that whipping movements of the wrench will be resisted for either rotational direction of the wrench relative to the workpiece.

The power wrench of the present invention may be driven by any suitable power source, such as air motors, hydraulic motors, electric motors, and the like. Preferably, the power unit for driving the worm gear and sprocket gear mechanism of the wrench is attachable to the wrench device when needed, and detachable when not needed. The power Wrench itself does not require a separate handle or support arm since extended bearing surfaces are provided on the housing to prevent whipping of the entire device. Thus, the power unit can be shaped as a detachable arm or handle which is inserted into the device when torque is to be applied to a nut. Also, the power unit should be reversible in its application of torque to a nut of bolt so that the wrench will not have to be repositioned for a reverse turning action.

The improved power wrench of this invention is used by placing the open socket member of the wrench over a nut which is to be turned. Then, the power unit is connected to the wrench and power can be applied to the wrench without any manual effort on the part of an operator. Application of power is continued until the turning operation is completed. Since the extended portions of the wrench housing prevent a turning or whipping of the wrench device, it is only necessary that an operator control the general position of the wrench and the power application, and there is no requirement for the operator to support the tool or to overcome reaction forces with his own strength.

These and other advantages of the present invention will become apparent in the more detailed discussion which follows, and in that discussion reference will be made to the accompanying drawings, as described below.

BRIEF DESCRIPTION OF DRAWINGS FIGURE 1 illustrates an elevational view of the general environment in which the improved wrench of this invention may be used;

FIGURE 2 is a top plan view of the wrench of this invention when it is being applied to connectors associated with blow-out preventor assembiles used in the oil industry;

FIGURE 3 is a top plan view of the improved wrench of this invention with a top housing plate removed and a section taken through a worm gear, as shown on lines 33 of FIGURE 4;

FIGURE 4 is an elevational, sectional view of the wrench taken at lines 44 of FIGURE 2;

FIGURE 5 is an elevational sectional view of the wrench taken at lines 55 of FIGURE 2;

FIGURE 6 is an end elevational view of the wrench taken at lines 66 of FIGURE 2; and

FIGURE 7 is an elevational section of a portion of the driving mechanism as seen at lines 7-7 of FIG- URE 3.

DESCRIPTION OF INVENTION FIGURE 1 illustrates the environment in which the improved power wrench of this invention is especially useful. In the illustrated use, a lower blow-out preventor valve 10 includes a flange 12 which is mated to a compression ring type of blow-out preventor valve 14 having a separate flange 16. The mating flanges 16 and 12 are typical of assemblies encountered in units which can be connected to well casings, and in a typical installation, a number of threaded studs 18 are inserted between the flanges and secured by nuts 20. Only one stud bolt with a nut is shown in FIGURE 1 for clarity, but it is to be understood that a number of closely spaced stud bolt positions are provided for connecting the flanges 12 and 16. The novel power wrench device of the present invention is shown in a lower position on the stud bolt 18, and a power unit 24 is illustrated as being attached to the wrench 22 for applying torque to the stud bolt 18. Of

course, it is to be understood that the wrench 22 can also be placed at an upper end of the stud bolt to apply torque to the nut 20. FIGURES 1 to 2 illustrate the space limitations within which the wrench must operate for use on a blow-out preventor assembly. In addition to the limitations dictated by the assembly itself, there are further space limitations with respect to the work area in which an assembly is normally positioned. Much of the work which must be accomplished on blow-out preventors takes place within a pit or dug-out area, and workmen must stand in precarious positions to reach down and apply torque to nuts on stud bolts for tightening or loosening flanges. Accordingly, it is important that a power wrench meet the dimensional limitations of a blow-out preventor assembly and of the place in which the work is to be performed.

FIGURE 2 is a top plan view of the power wrench 22 when positioned over a nut 20 of the type shown in FIGURE 1. It can be seen that a number of closely spaced stud bolts and nuts are positioned around the perimeter of a flange associated with the blow-out preventor assembly. An upright, cylindrical housing 26 of the blow-out preventor valve, or spacer collar, adjacent to the stud nuts, includes a perimeter which is very close to the positions of the nuts of the assembly. Thus, there is very little room for placing or turning a wrench in relation to stud bolt fasteners in an assembly of this type. As shown in FIGURE 2, the power wrench 22 has an outside configuration which permits the wrench to be inserted between nuts which adjoin a nut being turned. The power unit 24 does not form a separate part of the present invention, however, the power unit may be of any known type for relaying hydraulic, electrical, or other power to a mechanism within the power wrench 22. The power unit 24 is removable from the wrench, and it is possible to place the wrench in position without the power unit attached. Since the wrench includes a novel means for preventing rotation relative to the assembly upon which it is placed, there is no requirement for a separate handle to be grasped for resisting turning movement of the wrench or for applying turning movements to the wrench. The means for preventing whipping or swinging movements of the wrench, when power is applied thereto, comprises a novel configuration of a portion of the wrench housing. As shown in FIGURE 2, the extended por tions 28 of the wrench housing extend beyond the usual position for housing structures in wrenches of this type. The extended portions 28 are constructed to position an entire end of the wrench very closely to the perimeter of the cylindrical housing 26. The very small space which remains between the extended portions 28 of the wrench and the cylindrical housing 26 of the valve, limits any turning movement of the wrench about the longitudinal axis of the stud bolt which is being worked upon. When power is initially applied to the wrench, in one direction or the other, there is a very slight movement of the wrench body until contact is made between an extended portion 28 of the housing and the valve assembly. Once contact is made between one of the extended portions 28 and the cylindrical housing 26, no further movement of the wrench is possible, and thus, there is provided a firm bearing surface which prevents swinging or whipping of the wrench body once power is applied. With this arrangement, it is no longer required for an operator to resist the reaction forces of the wrench by his own efforts. The improved housing configuration of this invention provides for maximum housing strength and operator safety, as compared to prior art construction. If the extended portions 28 were removed, the entire wrench body would force itself against either of the nuts adjoining the one which is being turned, and this would be an unsafe arrangement for an operator and would permit an unsafe amount of travel for the wrench before it would be stopped.

FIGURES 3 through 7 illustrate details of the construction of the power wrench 22 of this invention. Basically, the wrench comprises a closed socket member 30 which includes gear teeth 32 about its entire circumference. The gear teeth of the socket member are driven by a worm gear 34 when power is applied to a shaft 58 upon which the worm gear is mounted. The socket member 30, and all driving mechanisms, are enclosed within a housing which is made up of two plates 36 and 38. As will be discussed in greater detail below, the entire structure for the wrench isvery sturdy and capable of handling forces encountered in oil field use. The direct drive which is provided for driving the gear teeth 32 of the socket member 30 eliminates any requirement for intermediate gear mechanisms, and the gear teeth 32 are protected within the confines of the housing plates 36 and 38 for all positions of the socket member 30.

Considering the wrench structure in greater detail, it can be seen that the closed socket member 30 is constructed with a socket opening 40 therethrough so that the socket member can be placed over whatever nut or stud bolt head is being worked upon. Gear teeth 32 are formed about the entire circumference of the socket member 30, and this is important, because an elimination of intermediate driving gears require a full circumference of gear teeth 32 for driving the socket member 30 in a full circle. It is contemplated that power will be applied to the wrench assembly in forward or reverse directions, and thus, it is essential that full circular travel of the socket be attainable without a requirement for repositioning the socket each time it is to be used. The socket member 30, and the driving mechanisms associated therewith, are enclosed, protected and supported by the two housing plates 36 and 38. As seen in FIGURES 4 through 6, the housing plates are constructed to provide bearing surfaces for the enclosed elements so that driving movement applied to the elements will be limited to the desired turning movement of the socket 30. Both plate members 36 and 38 include relatively large openings 42 for alignment with the socket opening 40. The lower plate 38 further includes a circular bearing opening 44 which extends into, but not through, the lower plate member so as to provide an uninterrupted, annular bearing surface 46 upon which a reduced diameter portion 48 (which is an annular extended portion of the socket 30) may be supported for its full circumference. There is no requirement for a similar bearing opening in the upper plate 36 since the face 50 of the upper plate 36 functions as a bearing surface for the socket member 30, thereby reducing the cost of manufacture for the wrench assembly. When the two housing plates 36 and 38 are assembled together by well-known fastening means 52, which may be in the form of nut and bolt assemblies, there is provided a sturdy structure for enclosing the socket member 30 and its associated gear teeth, and axial movements of the socket are limited by the bearing surfaces 46 and 50. Radial movements of the socket are prevented by the radial bearing surface 44 which receives the reduced diameter portion 48 of the socket member. The driving mechanism for the socket 30 includes the worm gear 34 and its driving connection with the gear teeth 32 of the socket member 30. The worm gear 34 is a cylindrical wor-m configuration, which is shown in the form of a tubular body, and is fitted within a recess 54 which is milled into the two plates 36 and 38 to provide for a lubricant reservoir within the housing. A grease fitting 56, or other lubricating means, may communicate with the reservoir 54 so that grease or other lubricant may be added when necessary. The worm gear 34 is mounted on a drive shaft 58 and is fixed in its position relative to the drive shaft by a key 60 fitted into key-ways formed on the drive shaft and within the worm gear. The drive shaft is carried within bearing elements 61 and 62, and axial movements of the worm gear are prevented by additional bearing elements 64 and 66. The entire drive shaft and worm gear assembly is mounted within the housing plates 36 and 38 for rotation therein, and the housing plates are milled out to receive the tubular hearing elements 61 and 62, as shown by the representative cross section of FIGURE 7. Either or both ends of the drive shaft may include an irregular recess 68 formed therein for receiving a driving member from a power source 24. The illustrated example of the construction shows a driving recess 68 at only one end of the drive shaft, and in this example, the power unit is applied to the end 70 of the wrench 22. Also, the driven end of the shaft 58 can be reinforced in its position within the wrench body by constructing the lower plate 38 with an upstanding reinforcing flange 71 which extends up to the outside surface of the upper plate 36. A bearing member 73 is inserted in a bore formed through the flange 71, and thus, a very firm mounting of the driven end of the shaft is provided. The bore in which the tubular bearing member 73 is inserted is formed completely within the profile of the flange 71 so that no stress forces are applied to the upper plate 36 when a power unit 24 is attached to the wrench.

The particular choice of a power source does not comprise a separate part of this invention, and any well-known power unit 24 may be utilized with the novel Wrench of this invention. For example, a reversible air motor of the type sold by Ingersoll-Rand under the Model No. 00BR2L56 may be used as a power unit 24. Since the wrench housing prevents any swinging or whipping movements of the entire wrench body, it is not necessary for a separate handle to be provided on the wrench, and therefore the power unit may comprise a unit of the type shown in FIGURE 2 which can be secured to the wrench for gripping by an operator when the wrench is in position for turning a nut or bolt. The power unit 24 may be secured to the end 70 of the wrench by well-known fastening devices (such as bolt means 77), or alternatively, the power unit can be releasably attached to the wrench as a form of removable handle means for the entire assem bly. Also, it is contemplated that the power unit 24 may include a calibrated gauge, of well-known construction, to indicate the amount of torque or power being applied to a workpiece.

Another feature of the present invention is a provision for complete protection of the socket member 30 and all of its gear teeth 32, while at the same time, providing for an inspection of the gear teeth. Because of the concave configuration 72 of the wrench housing, it can be seen that the socket 30 and all of its teeth 32 are entirely contained within the confines of the housing so as to be protected from any accidental damage to the gear teeth. However, a small portion of the lower plate 38 may be left open at 74, as shown in FIGURE 6, so that the gear teeth 32 are exposed for inspection. The gear teeth protrude beyond the opening 74 only slightly, and the extended portions 28 of the housing function to protect the exposed gear teeth from any accidental damage through the opening 74. Thus, it is possible to inspect the gears for Wear or damage. By assembling the housing plates 36 and 38 with bolt and nut fasteners 52, it is possible to disassemble the housing very quickly for replacement of any of the elements which are worn or which require maintenance.

The improved power wrench structure which has just been described can be used by simply placing the combined wrench body and power unit over the nut or bolt which is to be turned; or alternatively, the wrench body alone can be placed over the nut or bolt, and a removable power unit can be clamped to the wrench body in a driving relationship thereto. Then power is applied through the open recess 68 of the drive shaft so as to apply turning movements to the shaft, the worm gear, and the socket member 30. There is no requirement for an operator to resist movement of the wrench body, since the extended portions 28 prevent any swinging or whipping of the wrench body. The wrench can be positioned very quickly and easily in places having limited available space, and the wrench may be turned completely over so 7 that it can be used from either face of its thin, fiat body. A single operator can safely perform a tightening of blowout preventor studs with the wrench of this invention, and the dangerous use of hammers or additional devices to assist in the tightening operation is substantially eliminated.

What is claimed is:

1. A power operated wrench for working in confined places, comprising a housing means for completely enclosing and protecting a gear-driven socket member, said housing including first and second plate elements which can be fastened together in a face-to-face relationship for forming a thin, flat body for said power operated wrench, said first and second plate elements each having openings for-med therethrough for alignment with an open socket of said socket member, said housing means further including extended portions in spaced positions on one edge thereof for limiting whipping movement of the wrench when power is applied thereto, and said housing means having a generally concave configuration between said extended portions,

a socket member positioned within said housing for rotation therein, said socket member having a socket opening therethrough which is enclosed on all sides, and including gear teeth around the entire circumference of the socket member,

a worm gear means enclosed within said housing in a position for contacting and driving the socket member by engaging the gear teeth of said socket member, and

a drive shaft means for carrying said worm gear means within said housing, said drive shaft means having at least one end exposed through a wall portion of the housing for receiving turning movements from a power unit which can be positioned against the housing.

2. The power operated wrench of claim 1 wherein said first and second plate elements include bearing surfaces for preventing axial movements of said socket member.

3. A power operated wrench for working in confined places, comprising a housing means for completely enclosing and protecting a gear-driven socket member, said housing including first and second plate elements which can be fastened together in a face-to-face relationship for forming a thin, flat body for said power operated wrench, said first and second plate elements each having openings formed therethrough for alignment with an open socket of said socket member, and said housing further including extended portions on one edge for limiting whipping movement of the wrench when power is applied thereto,

a socket member positioned within said housing for rotation therein, said socket member having a socket opening therethrough which is enclosed on all sides, and including gear teeth around the entire circumference of the socket member,

a worm gear means enclosed within said housing in a position for contacting and driving the socket member by engaging the gear teeth of said socket member,

a drive shaft means for carrying said worm gear means within said housing, said drive shaft means having at least one end exposed through a wall portion of the housing for receiving turning movements from a power unit which can be positioned against the housing, and

said housing means including an inspection opening through one edge thereof for exposing gear teeth of said socket member which are in alignment with said inspection opening.

4. The power operated wrench of claim 3 wherein said inspection opening is included in the same edge of the housing which includes said extended portions, said inspection opening being positioned intermediate said extended portions so that any gear teeth which are exposed through said inspection opening are contained within the overall configuration of said housing.

5. The power operated wrench of claim 1 wherein said first plate element has a completely fiat inner face for contacting said second plate element and one face of said socket member, and wherein said second plate element includes a reduced diameter section extending into, but not through, said second plate member for contacting an opposite face of said socket member.

6. The power operated wrench of claim 5 wherein said reduced diameter portion is continuous and uninterrupted for supporting a completely circular face portion of said socket means.

7. The power operated wrench of claim 1 wherein said extended portions of said housing are positioned to contact adjacent structure of an object being worked upon so as to limit rotational movements of the wrench in either direction when power is applied thereto.

References Cited UNITED STATES PATENTS 685,544 10/1901 Weimar 8157 1,384,811 7/1921 Strand 8157 1,698,618 1/1929 Bigelow 81-57 2,481,633 9/1949 Wehner 8157 2,664,020 12/1953 De Note 81--52.4 2,780,944 2/1957 Ondeck 81-57 3,272,037 9/1966 Bruehl 81-57 JAMES L. JONES, 111., Primary Examiner 

